The Past, Present, and Future of Medical Marijuana in the United States

On October 19, 2009, the Office of the Deputy US Attorney General issued a memorandum, “Investigations and Prosecutions in States Authorizing the Medical Use of Marijuana.”1 The memo announced a federal policy to abstain from investigating or prosecuting “individuals whose actions are in clear and unambiguous compliance with existing state laws providing for the medical use of marijuana.” The memo made clear, however, that it did not “legalize marijuana or provide a legal defense to a violation of federal law.” Rather, it was “intended solely as a guide to the exercise of investigative and prosecutorial discretion.”

This article seeks to place the attorney general’s action in historical, medical, and legal context.

A concise medical history

Healers have turned to cannabis, known in the vernacular as marijuana, for its medicinal qualities for more than 5 millennia. Indeed, the world’s oldest surviving medical text, the Chinese Shen-nung Pen-tshao Ching, recommends marijuana to reduce the pain of rheumatism and to address digestive disorders.2

The herb had an established use in Western medicine, too. Between 1840 and 1900, more than 100 articles extolling its therapeutic virtues appeared in American and European medical journals.3 In 1851, the United States Pharmacopoeia included the “extract of hemp,” in its catalog of medicinal amalgams.4 That same year, The Dispensatory of the United States of America proclaimed, “The complaints in which [marijuana] has been specially recommended are neuralgia, gout, rheumatism, tetanus, hydrophobia, epidemic cholera, convulsions, chorea, hysteria, mental depression, insanity, and uterine hemorrhage.”5 A little more than a decade later, the 1864 edition of the Pharmacopoeia gave precise instructions in the preparation of this medicine.6

American physicians routinely prescribed marijuana until the late 1930s.7 It would not be until 1970 that the law would intervene to proscribe all uses of the herb.

Nonetheless, there remains controversy within the medical profession regarding both the safety and efficacy of medically prescribed inhaled marijuana smoke. (For a medical perspective on this topic, see the Commentary by Ronald Pies, MD.) For example, one recent review noted that “tetrahydrocannabinol (THC) and other [cannabinoid-1] receptor agonists can have an undesirable CNS impact, and, in many cases, dose optimization may not be realizable before onset of excessive side effects. . . . [moreover] cannabis herbal material (“medical marijuana”) may present fatal uncertainties of quality control and dosage standardization. Therefore, formulation, composition, and delivery system issues will affect the extent to which a particular cannabinoid product may have a desirable risk-benefit profile and acceptable abuse liability potential.”8

Furthermore, medical marijuana use may pose particular problems for some psychiatric patients, since marijuana may exacerbate positive symptoms of schizophrenia and increase the risk of psychotic relapse.9

A concise legal history

The Marijuana Tax Act of 1937 was the first federal restriction on the herb’s use and distribution.10 It imposed a $1 per ounce tax on marijuana purchased for medical purposes and $100 per ounce for any other purchases. In an early example of the health care policy chicanery that today’s physicians know all too well, the act imposed sufficiently onerous paperwork requirements for medicinal use that physicians ceased prescribing the herb shortly after its enactment.11